Just saw this post of yours.
I'm wanting to build a metric Joes as well but time is a major issue at the moment.
I am not aware of a full set of metric Joes plans as yet, and I was trying to convert them myself but have been struggling due to my lack of CAD skills.
In the mean time, I bought myself a small and very solid CNC machine which I will use until I have the time to build the bigger machine.
Scott in Sydney is cutting one manually and has done a great job so far. His log is here;
Handcut Joes in Sydney, Australia